Richard J. French

Vapor phase release of alkali species in the combustion of biomass pyrolysis oils

Abstract For the first time, emission of alkali vapor species from biomass is being directly observed, under combustion conditions, by molecular beam mass spectrometry. The free jet sampling system cools the products of combustion extremely rapidly with little condensation, making it possible to identify the alkali species that are active in high-temperature vapor transport. Recent results are discussed in light of the mechanisms of release and the implications for the use of biomass in gasification and combustion systems. The paper also includes a substantial review of literature relative to alkali in biomass and its behavior vis-a-vis coal.

Production of Hydrogen from Biomass by Pyrolysis/Steam Reforming

We successfully demonstrated that hydrogen could be efficiently produced by catalytic steam reforming of carbohydrate-derived bio-oil fractions in a fluidized bed reactor using a commercial nickel-based catalyst. Greater steam excess than that used for natural gas reforming was necessary to minimize the formation of char and coke (or to gasify these carbonaceous solids) resulting from thermal decomposition of complex carbohydrate-derived compounds.

Biomass Conversion to Produce Hydrocarbon Liquid Fuel Via Hot-vapor Filtered Fast Pyrolysis and Catalytic Hydrotreating.

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and the processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. The protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.

Driving towards cost-competitive biofuels through catalytic fast pyrolysis by rethinking catalyst selection and reactor configuration

Catalytic fast pyrolysis (CFP) has emerged as an attractive process for the conversion of lignocellulosic biomass into renewable fuels and products. Considerable research and development has focused on using circulating-bed reactors with zeolite catalysts (e.g., HZSM-5) for CFP because of their propensity to form gasoline-range aromatic hydrocarbons. However, the high selectivity for aromatics comes at the expense of low carbon yield, a key economic driver for this process. In this contribution, we evaluate non-zeolite catalysts in a fixed-bed reactor configuration for an integrated CFP process to produce fuel blendstocks from lignocellulosic biomass. These experimental efforts are coupled with technoeconomic analysis (TEA) to benchmark the process and guide research and development activities to minimize costs. The results indicate that CFP bio-oil can be produced from pine with improved yield by using a bifunctional metal-acid 2 wt% Pt/TiO2 catalyst in a fixed-bed reactor operated with co-fed H2 at near atmospheric pressure, as compared to H-ZSM5 in a circulating-bed reactor. The Pt/TiO2 catalyst exhibited good stability over 13 reaction-regeneration cycles with no evidence of irreversible deactivation. The CFP bio-oil was continuously hydrotreated for 140 h time-on-stream using a single-stage system with 84 wt% of the hydrotreated product having a boiling point in the gasoline and distillate range. This integrated biomass-to-blendstock process was determined to exhibit an energy efficiency of 50% and a carbon efficiency of 38%, based on the experimental results and process modelling. TEA of the integrated process revealed a modelled minimum fuel selling price (MFSP) of

Catalytic pyrolysis of biomass for biofuels production

4.34 per gasoline gallon equivalent (GGE), which represents a cost reduction of

Catalytic steam reforming of bio-oils for the production of hydrogen: effects of catalyst composition

0.85 GGE−1 compared to values reported for CFP with a zeolite catalyst. TEA also indicated that catalyst cost was a significant factor influencing the MFSP, which informed additional CFP experiments in which lower-cost Mo2C and high-dispersion 0.5 wt% Pt/TiO2 catalysts were synthesized and evaluated. These materials demonstrated CFP carbon yield and oil oxygen content similar to those of the 2 wt% Pt/TiO2 catalyst, offering proof-of-concept that the lower-cost catalysts can be effective for CFP and providing a route to reduce the modelled MFSP to

Hydrogen by catalytic steam reforming of liquid byproducts from biomass thermoconversion processes

3.86–3.91 GGE−1. This report links foundational science and applied engineering to demonstrate the potential of fixed-bed CFP and highlights the impact of coupled TEA to guide research activities towards cost reductions.